643825 has 24 divisors (see below), whose sum is σ = 986048. Its totient is φ = 406080.

The previous prime is 643781. The next prime is 643847. The reversal of 643825 is 528346.

It is not a de Polignac number, because 643825 - 2⁷ = 643697 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 643793 and 643802.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2134 + ... + 2416.

2⁶⁴³⁸²⁵ is an apocalyptic number.

643825 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

643825 is a deficient number, since it is larger than the sum of its proper divisors (342223).

643825 is a wasteful number, since it uses less digits than its factorization.

643825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 313 (or 308 counting only the distinct ones).

The product of its digits is 5760, while the sum is 28.

The square root of 643825 is about 802.3870637043. The cubic root of 643825 is about 86.3487282250.

The spelling of 643825 in words is "six hundred forty-three thousand, eight hundred twenty-five".